We are continuing our studies on ligand receptor effects on lymphocytes and on the pathophysiology of phagocytes. The experiments specifically involve: 1) an evaluation of the role of contractile proteins and ions in capping of surface complexes; 2) a comparative analysis of the response to ligands of different types of B cells; and 3) a study of B cell motility produced by antigens. The experiments on macrophages involve biochemical characterization of molecules which modulate lymphocyte function. BIBLIOGRAPHIC REFERENCES: Schreiner, G.F. and Unanue, E.R. The modulation of spontaneous and anti-Ig-stimulated motility of lymphocytes by cyclic nucleotides and adrenergic and cholinergic agents. J. Immunol., 114:802, 1975. Calderon, J. and Unanue, E.R. An evaluation of the role of macrophages in immune induction. Fed. Proc., 34:1737, 1975.